A biofuel cell is a fuel cell that uses enzymes or micro-organisms, such as bacteria, to convert some of the energy available in a biodegradable substrate into electricity.
In general, a biofuel cell comprises an electrode, forming the anode, placed in contact with enzymes for the transformation of the biodegradable substrate, for example glucose, in particular by electrons captured by the anode. The biofuel cell also comprises a cathode at which an electron acceptor, for example air, is reduced, for example to water.
A potential difference therefore appears between the anode and the cathode when these are connected to a load.
There are many publications in the biofuel cell field.
Mention may particularly be made of the article by Philippe Cinquin, et al. entitled “A Glucose BioFuel Cell Implanted in Rats”, PLoS ONE/www.plosone.org, May 2010/volume 5/Issue 5/e10476 (the disclosure of which is incorporated by reference), which describes the production of an experimental biofuel cell implanted into a rat. This biofuel cell is capable of producing in vivo electricity by virtue of the aforementioned redox phenomenon from oxygen and glucose that are present in the physiological fluids of the rat. Two different powders are used at the anode and cathode respectively.
Mention may also be made of the article by Lewis Dartnell, entitled “Sparks of Life” available at the Internet address http://www.ucl.ac.uk/˜ucbplrd/sparks_page.htm (the disclosure of which is incorporated by reference). This article describes a biofuel cell using bacteria called Rhodoferax ferrireducens at the anode.
Industrially acceptable solutions should now be proposed in particular for reducing the size of the implants and to increase the power generated by these biofuel cells.